Uniswap 对 = address(uint(keccak256(abi.encodePacked() 错误

Question

我不明白为什么当我尝试编译我的合约以交换不同 dex 上的代币时会出现此错误。

这里的代码：

//SPDX-License-Identifier: MIT

import "./Interfaces/IUniswapV2Router02.sol";
import "./Interfaces/IUniswapV2Factory.sol";
//import "./Interfaces/IUniswapV2Pair.sol";
import "./Interfaces/IERC20.sol";
import "./Interfaces/UniswapV2Library.sol";
//import "./Interfaces/IUniswapV2Callee.sol";


pragma solidity >0.5.0 < 0.9.0;

contract SwappingDex{

    address public constant uniswapRouter = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    address public constant uniswapFactory = 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f;
    address public constant sushiSwapRouter = 0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F;
    address public constant sushiSwapFactory = 0xC0AEe478e3658e2610c5F7A4A2E1777cE9e4f2Ac;
    address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;


    function swappingIn2DEX(address tokenIn, address tokenOut, uint amount, address to)external payable{

        address pairOnUniswap;
        address pairOnSushi;
        pairOnUniswap = IUniswapV2Factory(uniswapFactory).getPair(tokenIn, tokenOut);
        pairOnSushi = IUniswapV2Factory(sushiSwapFactory).getPair(tokenIn, tokenOut);

        require(
            pairOnSushi != 0x0000000000000000000000000000000000000000 &&
            pairOnUniswap != 0x0000000000000000000000000000000000000000,
            "No Pair"
        );

        address[] memory path;
        path = new address[](2);
        path[0] = tokenIn;
        path[1] = tokenOut;

        uint[]memory amountOutUniswap = IUniswapV2Router02(uniswapRouter).getAmountsOut(amount, path);


        IERC20(tokenIn).transferFrom(msg.sender, address(this), amount);
        IERC20(tokenIn).approve(uniswapRouter, amount);

        IUniswapV2Router02(uniswapRouter).swapETHForExactTokens{value: msg.value}(
            amountOutUniswap[1],
            path,
            to,
            block.timestamp
        );
}

安全帽.config.js

require("@nomiclabs/hardhat-waffle");
require("@nomiclabs/hardhat-ethers");
require("dotenv").config();


module.exports = {
  solidity: "0.8.4",

  networks: {
    hardhat: {
      forking:{
        url: "*******",
      },
    },
  }
};

一旦我去编译，通过 npx hardhat 编译，我得到这个错误：

类型错误：不允许从“uint256”到“地址”的显式类型转换。 --> 合同/接口/UniswapV2Library.sol:20:16: | 20 |对=地址（uint（keccak256（abi.encodePacked（ | ^（相关源代码部分从这里开始并跨越多行）。

我正在寻找一些关于它的原因，我看到一些关于在 ^0.8.0 版本之后地址转换的内容。 我已经用相同的步骤在 uniswap 上做了项目，但这是我第一次遇到这个错误。 有人可以解释我为什么吗？ 非常感谢！

Answer 1

这是UniswapV2Library.sol github repo。代码抱怨这个

function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(uint(keccak256(abi.encodePacked(
                hex'ff',
                factory,
                keccak256(abi.encodePacked(token0, token1)),
                hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f' // init code hash
            ))));
    }

您需要应用 UNiswap repo 的设置。该仓库正在使用ethereum-waffle.readthedocs，如果您检查项目根目录中的.waffle.json 配置，您会看到以下设置：

{
  "compilerVersion": "./node_modules/solc",
  "outputType": "all",
  "compilerOptions": {
    "outputSelection": {
      "*": {
        "*": [
          "evm.bytecode.object",
          "evm.deployedBytecode.object",
          "abi",
          "evm.bytecode.sourceMap",
          "evm.deployedBytecode.sourceMap",
          "metadata"
        ],
        "": ["ast"]
      }
    },
    "evmVersion": "istanbul",
    "optimizer": {
      "enabled": true,
      "runs": 999999
    }
  }
}

UniswapV3 也有类似的问题，我问了a question here and then answered。我使用安全帽，并应用了 UniswapV3 存储库中的这些设置。

const DEFAULT_COMPILER_SETTINGS = {
  version: '0.7.6',
  settings: {
    evmVersion: 'istanbul',
    optimizer: {
      enabled: true,
      runs: 1_000_000,
    },
    metadata: {
      bytecodeHash: 'none',
    },
  },
}

我认为主要原因是使用evmVersion: 'istanbul',